The present invention relates in general to mineral mining installations and more particularly to installations employing a mineral winning machine equipped with rotary cutting means, such as cutter drums.
It is known to win mineral, especially coal, with the aid of a shearer which has cutter drums supported on pivotable arms. The cutter drums are usually driven by drive means, such as one or more three-phase a.c. motors, mounted on the main body or structure of the shearer or winning machine. The machine is also provided with further drive means which effects the actual movement of the machine in relation to the mineral face. This further drive means can take a variety of different forms. For example, a chain drive system with a winch or the like can be adopted or a chainless propulsive system can serve to move the overall machine. Hydraulic or electric power can serve to propell the machine and in the latter case a d.c. motor is quite conventional.
A general object of the present invention is to provide an improved form of mineral mining installation of the aforementioned kind.
An installation constructed in accordance with the invention utilizes a winning machine of the shearer type, i.e. with rotary cutting means, and a dynamic control system which optimize the performance of the machine. The control system continuously controls the propulsive speed of the machine in dependence on the performance, e.g. power consumption, of the cutting means i.e. the cutter drum or drums. Hence, depending on the prevailing conditions, and particularly the hardness of the mineral face, the machine is driven at an appropriate speed. One convenient system for achieving this objective has a frequency converter which provides variable-frequency a.c. power to a motor which determines the propulsive speed of the machine. The various monitoring and control devices which make up this control system are mounted remote from the machine and conveniently in a control station located in a gallery or roadway outside the main working. The devices making up the control system are thus well protected. A cable and/or bushbar can link the machine to the control station.
Power can be supplied to the machine via the cable and the performance monitoring information can also pass along this cable. The drive means which propels the machine or determines the propulsive speed of the machine preferably takes the form of a three-phase a.c. asynchronous motor which is fed by the frequency converter. Monitoring means in the control station can sense the power consumption of the cutter drum or drums and control the frequency converter accordingly. The cutter drum or drums can also be driven by one or more three-phase a.c. motors. The power for all the motors can be conveyed via a composite cable.
A mineral mining installation constructed in accordance with the invention may comprise a winning machine with a main body equipped with at least one rotary cutting means, first drive means carried on the body for driving the cutting means, second drive means carried on the body for moving the machine and an electronic control system remote from the machine for controlling the second drive means in dependence on the operation of the cutting means.
A self-propelled shearer driven by a three-phase a.c. motor built on to its body structure and having a further a.c. motor driving at least one cutter drum thereof can be improved by the provision of a control station separate from the machine in a gallery or roadway outside the main working in which the shearer operates, a composite cable electrically connecting the motors to the control station, monitoring means in the control station for remotely sensing a function of the motor driving the cutter drum signifying the performance of the latter and control means in the control station for controlling the operational speed of the motor driving the machine in accordance with the performance as sensed by the monitoring means.
The invention may be understood more readily, and various other features of the invention may become apparent, from consideration of the following description.